Tuesday, 23 May 2017

Experimenting with concrete planters

A few months back a video started making the rounds showing how to make concrete dragon eggs. You can watch the video Here.
The video used them as candle holders. Being keen on experiments that
weekend out came the plaster-of-paris and the balloons, yes sadly we
have both lieing aroud the house. The plaster ones came out really
easily with only minor modifications of havig to turn the eggs
constantly for about 10 minutes then leaving for about 30 minutes.

A few more were made and have been put aside ready to invite one my newphews around to decorate.

While
they would make excellent candle holders my first thought was always as
planters, especially if the concrete worked. So a trip to the hardware
shop to buy some quick drying concrete and time to try my first
concrete egg. It looks so easy on the film: mix the concrete with
water, pour into balloon, turn every two minutes for 2 hours. I ended
up with a lump of concrete.

Four attempts later

I
have watched several different videos now and they all simply say, turn
every two minutes. I don't know if I am usig different cement, but it
just doesn't work for me. Instead I have found shaking, then turning,
then shaking, then turning. The reason for the shaking is that if the
concrete hardens giving the ballon a good shake softens it again, giving
you another go.

Tip: leave the eggs for at least 12 hours
to harden before bursting the balloon. Again after only 2 hours it was
no where near enough, and even after 6 or 7 if the concrete was too
thin, the egg just crumbled.

Now the big warning.
Do not do this inside, especially not in your best room, while sitting
on your new furniture with you OH and the dog. Yes sadly I do speak
from experience and amazingly I am still married and alive! We both
wish we had taken a photos, as it went everywhere. I'm not sure if you
have ever tried bursting a balloon filled with water, but shaking and
then looked at how far it spreds. It is very effective, the carpet,
walls, furniture, pets and us all covered.

So lesson
learnt. In fact I found puttting the ballon in a plastic bag saved a
lot of mess should things go wrong when popping the ballon as well.

Once
you have the eggs, you can make holes. Again the video makes it look
easy, but make your egg too thin and the slightest pressure and they
crumble. I have a nice collection of concrete bits in a bin in the
greenhouse. My tip here would be to leave the egg for 24 hours to let
it harden a bit more, and to check it over for cracks so you know the
weak points.

Then you can reinforce it. This was
probably the easiest bit, mix some vert liquick concrete mix, pour it
into the egg and swivle it around to coat the inside. You do have to
keep an eye on cracks don't be tempted to over do it the first time. It
was better to do three layers, leaving the layers to dry between. The
first layer is the crucial one, especially while turning the egg as it's
easy to crush it.

While
doing all of this I tried adding different coloured powder to the
concrete to colour the eggs. The red looks great when wet, but is very
pale dry.

Black
probably has the most promise. This was the last egg I tried and is
the most sucesfull. I learnt that blowing the ballon up and leaving it
blown up until you are ready to pour the concrete in allows you to get
more in and so to have thicker walls.

I
am toying with differet ways to finish them. The first few were soaked
in water for a couple of weeks, changing the water every day. This
should help leach out some of the stuff plants do not like. The other
options are concrete sealer, and painting.

Then you can drill drainage holes and plant them up.

I've
got a few more to plant up, I'll save them for another post. I'm
probably going to try a few differet plants for differet parts of the
garden. They probably lend themselves more to the clump forming plants
than the agaves, but I'll have to try one with an agave in. I think they
would be great with a mound forming succulent flowing over the egg.

Now go away and try them for yourselves and show me how you would plant them up.